In the practice of control the industrial processes, proportional-integral-derivative controller remains pivotal due to its simple structure and system performance-oriented tuning process. In this paper are presented ...In the practice of control the industrial processes, proportional-integral-derivative controller remains pivotal due to its simple structure and system performance-oriented tuning process. In this paper are presented two approaches for synthesis the proportional-integral-derivative controller to the models of objects with inertia, that offer the procedure of system performance optimization based on maximum stability degree criterion. The proposed algorithms of system performance optimization were elaborated for model of objects with inertia second and third order and offer simple analytical expressions for tuning the PID controller. Validation and verification are conducted through computer simulations using MATLAB, demonstrating successful performance optimization and showcasing the effectiveness PID controllers’ tuning. The proposed approaches contribute insights to the field of control, offering a pathway for optimizing the performance of second and third-order inertial systems through robust controller synthesis.展开更多
We have succeeded in 2-slit interference simulation by assuming that a travelling particle interacts with its environment, getting information on the environmental condition according to the adaptive dynamics by Ohya,...We have succeeded in 2-slit interference simulation by assuming that a travelling particle interacts with its environment, getting information on the environmental condition according to the adaptive dynamics by Ohya, thus proposed the possibility that the entanglement comes from the interaction with the environment (Ando et al., 2023). This concept means that there should be no isolated or inertial system other than our unique universe space. Taking this message into account and assuming that the signal velocity is constant against our unique universe space, we reconsidered the inertial system and relativity theory by Galilei and Einstein and found several misunderstandings and errors. Time delay and Lorentz shrinkage were derived similarly to the prediction by special relativity theory, but Lorentz transformation and 4-dimensional time/space view were not. They must have implicitly and unconsciously assumed that any signals transfer information without giving any influences to any systems different from our adaptive dynamical view. We propose that their relativity theories should be reinterpreted in view of adaptive dynamics.展开更多
In this paper, I present evidence that there exists an unstructured area in the present general assumptions of classical mechanics, especially in case of rigid bodies exposed to simultaneous noncoaxial rotations. To a...In this paper, I present evidence that there exists an unstructured area in the present general assumptions of classical mechanics, especially in case of rigid bodies exposed to simultaneous noncoaxial rotations. To address this, I propose dynamics hypotheses that lead to interesting results and numerous noteworthy scientific and technological applications. I constructed a new mathematical model in rotational field dynamics, and through this model, results based on a rational interpretation of the superposition of motions caused by torques were obtained. For this purpose, I analyze velocity and acceleration fields that are generated in an object with intrinsic angular momentum, and assessed new criteria for coupling velocities. In this context, I will discuss reactions and inertial fields that cannot be explained by classical mechanics. The experiments have been analyzed and explained in a video accompanying this text. I am not aware of any concurrent study on the subject and conclusions evidenced in this paper, preventing us from making additional theoretical com- parisons or indicate to the reader other sources to compare criteria.展开更多
Inertial system platforms are a kind of important precision devices,which have the characteristics of difficult acquisition for state data and small sample scale.Focusing on the model optimization for data-driven faul...Inertial system platforms are a kind of important precision devices,which have the characteristics of difficult acquisition for state data and small sample scale.Focusing on the model optimization for data-driven fault state prediction and quantitative degreemeasurement,a fast small-sample supersphere one-class SVMmodelingmethod using support vectors pre-selection is systematically studied in this paper.By theorem-proving the irrelevance between themodel’s learning result and the non-support vectors(NSVs),the distribution characters of the support vectors are analyzed.On this basis,a modeling method with selected samples having specific geometry character fromthe training sets is also proposed.The method can remarkably eliminate theNSVs and improve the algorithm’s efficiency.The experimental results testify that the scale of training samples and the modeling time consumption both give a sharply decrease using the support vectors pre-selection method.The experimental results on inertial devices also show good fault prediction capability and effectiveness of quantitative anomaly measurement.展开更多
The physical nature of inertia is explored. Authors, based on Mach’s principle, offer hypothesis of the induction nature of inertia and theory, which allows extend the principle of relativity to the non-inertial refe...The physical nature of inertia is explored. Authors, based on Mach’s principle, offer hypothesis of the induction nature of inertia and theory, which allows extend the principle of relativity to the non-inertial reference systems. The system of differential equations, which eliminates the shortcomings of Newtonian mechanics and Special Theory of Relativity (STR) was composed according to this theory. Row of concrete calculations and explanations are made using the theory. Reason of constancy orbital velocities of galaxies is found out and way of its calculations is shown. Existence of dark matter and the new particles (neutralinos, axons, space vacuum etc.) is prejudiced. Axial deviation of the ray of light in gravitational field is explained and calculated. An example of calculation of the Mercury’s orbital motion is made and complex planets’ trajectories are explained by the action of new field with induction nature. Flat rotation of celestial bodies and shaping of planets’ rings (like the Saturn’s rings) are explained. Indistinguishability of Doppler and Einstein’s effects for terrestrial observer is shown.展开更多
Microelectromechanical systems(MEMS)technology has gained significant attention over the past decade for measuring inertial angular velocity.However,due to inherent complexity,MEMS gyroscopes typically feature up to t...Microelectromechanical systems(MEMS)technology has gained significant attention over the past decade for measuring inertial angular velocity.However,due to inherent complexity,MEMS gyroscopes typically feature up to ten times more parameters than traditional sensors,making selection a challenging task even for experts.This study addresses this challenge,focusing on defensive guidance,navigation,and control(GNC)systems where precise and reliable angular velocity measurement is critical to overall performance.A comprehensive mathematical model is introduced to encapsulate all key MEMS parameters,accompanied by discussions on calibration and Allan variance interpretation.For six leading MEMS gyroscope applications,namely inertial navigation,integrated navigation,autopilot systems,rotating projectiles,homing guidance,and north finding,the most critical parameters are identified,distinguishing suitable and unsuitable sensor choices.Special emphasis is placed on inertial navigation systems,where practical rules of thumb for error evaluation are derived using six degrees of freedom motion equations.Rigorous simulations demonstrate the influence of various sensor parameters through real-world case studies,including static navigation,multi-rotor attitude estimation,gimbal stabilization,and north finding via a turntable.This work aims to be a beacon for practitioners across diverse fields,empowering them to make more informed design decisions.展开更多
A shaking table test was performed to investigate the different responses of piles with and without cement-soil reinforcement,considering both inertial and kinematic interactions.A comparison of the dynamic shear stre...A shaking table test was performed to investigate the different responses of piles with and without cement-soil reinforcement,considering both inertial and kinematic interactions.A comparison of the dynamic shear stress−strain hysteresis curves of soil profiles on the pile side with and without cement-soil reinforced piles indicates that cement-soil reinforced piles not only bear more tremendous shear stress but also have smaller strains under the action of cyclic shear stress.Furthermore,the cement-soil on the pile side not only shares part of the shear stress and modifies the bending moment distribution but also significantly enhances the resistance of the pile-side soil,reducing the lateral displacement of the superstructure.Cement-soil reinforcement reduced shear strains,inhibited sand liquefaction,and reduced superstructure displacements by 27%−47%(instantaneous)and 40%−65%(permanent).The proportion of horizontal load sharing between cement-soil reinforcement and saturated sand is considered,along with the change pattern of the subgrade reaction after sand liquefaction.An equivalent subgrade reaction calculation method is proposed,which accounts for the horizontal load-sharing ratios of soils with two different strengths.The test results indicate that the pile stress and displacement,estimated using the equivalent subgrade reaction,are in good agreement with the observed results.展开更多
The suppression of ablative Rayleigh–Taylor instability(ARTI)by a spatially modulated laser in inertial confinement fusion(ICF)is studied through numerical simulations.The results show that in the acceleration phase ...The suppression of ablative Rayleigh–Taylor instability(ARTI)by a spatially modulated laser in inertial confinement fusion(ICF)is studied through numerical simulations.The results show that in the acceleration phase of ICF implosion,the growth of ARTI can be suppressed by using a short-wavelength spatially modulated laser.The ARTI growth rate decreases as the wavelength of the spatially modulated laser decreases,and ARTI is completely suppressed after a certain wavelength has been reached.A spatially uniform laser is introduced to keep the state of motion of the implosion fluid consistent,and it is found that the proportion of the spatially modulated laser required for complete suppression of ARTI decreases as the wavelength continues to decrease.We also optimize the spatial intensity distribution of the spatially modulated laser.In addition,as the duration of the spatially modulated laser decreases,the proportion required for completely suppressing ARTI increases,but the required energy decreases.When the perturbation wavenumber decreases,the wavelength of the spatially modulated laser required for complete suppression of ARTI becomes longer.In the case of multimode perturbation,ARTI can also be significantly suppressed by a spatially modulated laser,and the perturbation amplitude can be reduced to less than 10% of that without a spatially modulated laser.We believe that the conclusions drawn from our simulations can provide the basis for new approaches to control ARTI in ICF.展开更多
The principle of the inertial navigation system（INS） with rotating inertial measurement unit （IMU） is analyzed. A new IMU is established to rotate round each axis in three directions. Then, the related error model...The principle of the inertial navigation system（INS） with rotating inertial measurement unit （IMU） is analyzed. A new IMU is established to rotate round each axis in three directions. Then, the related error models for the designed system during rotating are deduced and the improved system is built. Finally, the performance simulation of the proposed system is provided. The simulation result indicates that the designed system can improve the accuracy of the roll and the pitch as well as heading by rotating three axes, thus guaranting the heading accuracy. Moreover, based on the principle of rotation at six different positions, such structure can carry out real-time calibration, and improve the system performance.展开更多
Based on error analysis, the influence of error sources on strapdown inertial navigation systems is discussed. And the maximum permissible component tolerances are established. In order to achieve the desired accuracy...Based on error analysis, the influence of error sources on strapdown inertial navigation systems is discussed. And the maximum permissible component tolerances are established. In order to achieve the desired accuracy (defined by circular error probability), the types of appropriate sensors are chosen. The inertial measurement unit (IMU) is composed of those sensors. It is necessary to calibrate the sensors to obtain their error model coefficients of IMU. After calibration tests, the accuracy is calculated by uniform design method and it is proved that the accuracy of IMU is satisfied for the desired goal.展开更多
A brand new method of automatic north seeking/sight stabilizing is introduced for usage in land fighting vehicles such as tank, etc. Some inertial devices are installed additionally on the platform along with relat...A brand new method of automatic north seeking/sight stabilizing is introduced for usage in land fighting vehicles such as tank, etc. Some inertial devices are installed additionally on the platform along with relative control circuits to make its function of North seeking possible. Double position calculation is adopted in this method, and by alignment at two sites the azimuth angle can be figured out. Also the orientation and the horizontal shifts of the gyro are simultaneously measured and compensated so as to improve the accuracy of north seeking. The system can automatically seek north when the vehicle is immobile. And the time consumption is no more than 5.5 min. Besides, the system can keep azimuth angle and provide tilt angle and pitch angle of the vehicle.展开更多
Due to the poor observability of INS ground self alignment, only horizontal alignment is satisfied. This paper proposes using GPS double difference carrier phase as external reference to improve the observability of ...Due to the poor observability of INS ground self alignment, only horizontal alignment is satisfied. This paper proposes using GPS double difference carrier phase as external reference to improve the observability of INS self alignment. Through observability analysis and computer simulation, it is demonstrated that the azimuth alignment is as quick as horizontal alignment, the accuracy of horizontal alignment is improved, and the gyros errors can be estimated quickly and precisely.展开更多
The cost of the gravity passive inertial navigation system will be lower witha rate azimuth platform and gravity sensor constituting a gravity measurement and navigationsystem. According to the system performance char...The cost of the gravity passive inertial navigation system will be lower witha rate azimuth platform and gravity sensor constituting a gravity measurement and navigationsystem. According to the system performance characteristics, we study the rate azimuth platforminertial navigation system (RAPINS), give the system navigation algorithm, error equations of theattitude, velocity and position of the rate azimuth platform, and random error models of theaccelerometer and gyro. Using the MATLAB/Simulink tools, we study the RAPINS and RAPINS withvelocity damping. Simulation results demonstrate that the RAPINS with velocity damping has smallerrors in platform attitude and position and satisfies gravity measurement and navigationrequirement.展开更多
With the development of micro-electromechanical systems(MEMS), miniaturized, low-power and low-cost inertial measurement units(IMUs) have been widely integrated into mobile terminals and smart wearable devices. This p...With the development of micro-electromechanical systems(MEMS), miniaturized, low-power and low-cost inertial measurement units(IMUs) have been widely integrated into mobile terminals and smart wearable devices. This provides the prospect of a broad application for the inertial sensor-based pedestrian dead-reckoning(IPDR) systems. Especially for indoor navigation and indoor positioning, the IPDR systems have many unique advantages that other methods do not have. At present, a large number of technologies and methods for IPDR systems are proposed. In this paper, we have analyzed and outlined the IPDR systems based on about 80 documents in the field of IPDR in recent years. The article is structured in the form of an introduction-elucidation-conclusion framework. First, we proposed a general framework to explore the structure of an IPDR system. Then, according to this framework, the IPDR system was divided into six relatively independent sub-problems, which were discussed and summarized separately. Finally, we proposed a graph structure of IPDR systems, and a sub-directed graph, formed by selecting a combined path from the start node to the end node, skillfully constitutes a technical route of one specific IPDR system. At the end of the article, we summarized some key issues that need to be resolved before the IPDR systems are widely used.展开更多
In this work,a fast and accurate stationary alignment method for strapdown inertial navigation system （SINS） is proposed. It has been demonstrated that the stationary alignment of SINS can be improved by employing t...In this work,a fast and accurate stationary alignment method for strapdown inertial navigation system （SINS） is proposed. It has been demonstrated that the stationary alignment of SINS can be improved by employing the multiposition technique,but the alignment time of the azimuth error is relatively longer. Over here, the two-position alignment principle is presented. On the basis of this SINS error model, a fast estimation algorithm of the azimuth error for the initial alignment of SINS on stationary base is derived fully from the horizontal velocity outputs and the output rates, and the novel azimuth error estimation algorithm is used for the two-position alignment. Consequently, the speed and accuracy of the SINS＇ s initial alignment is enhanced greatly. The computer simulation results illustrate the efficiency of this alignment method.展开更多
A new simple and effective inertial parameter identification method based on sinusoidal vibrations of a six-degree-of-freedom parallel manipulator is proposed. Compared with previously known identification algorithms,...A new simple and effective inertial parameter identification method based on sinusoidal vibrations of a six-degree-of-freedom parallel manipulator is proposed. Compared with previously known identification algorithms, the advantages of the new approach are there is no need to design the excitation trajectory to consider the condition number of the observation matrix and the inertial matrix can be accurately defined regardless of the effect of viscous friction. In addition, the use of a sinusoidal exciting trajectory allows calculation of the velocities and accelerations from the measured position response. Simulations show that the new approach has acceptable tolerance of dry friction when using a simple coupling parameter modified formula. The experimental application to the hydraulically driven Stewart platform demonstrates the capability and efficiency of the proposed identification method.展开更多
To improve the accuracy of strapdown inertial navigation system(SINS) for long term applications,the rotation technique is employed to modulate the errors of the inertial sensors into periodically varied signals,and,a...To improve the accuracy of strapdown inertial navigation system(SINS) for long term applications,the rotation technique is employed to modulate the errors of the inertial sensors into periodically varied signals,and,as a result,to suppress the divergence of SINS errors.However,the errors of rotation platform will be introduced into SINS and might affect the final navigation accuracy.Considering the disadvantages of the conventional navigation computation scheme,an improved computation scheme of the SINS using rotation technique is proposed which can reduce the effects of the rotation platform errors.And,the error characteristics of the SINS with this navigation computation scheme are analyzed.Theoretical analysis,simulations and real test results show that the proposed navigation computation scheme outperforms the conventional navigation computation scheme,meanwhile reduces the requirement to the measurement accuracy of rotation angles.展开更多
The error equation of a rotating inertial navigation system was introduced. The effect of the system's main error source (constant drift of gyro and zero bias of accelerometer) under rotating conditions for the sy...The error equation of a rotating inertial navigation system was introduced. The effect of the system's main error source (constant drift of gyro and zero bias of accelerometer) under rotating conditions for the system was analyzed. Validity of theoretical analysis was shown via simulation, and that provides a theoretical foundation for a rotating strap-down inertial navigation system during actual experimentation and application.展开更多
This article proposes a new inner attitude integration algorithm to improve attitude accuracy of the strapdown inertial attitude and heading reference system(SIAHRS),which,by means of a Kalman filter,integrates the ca...This article proposes a new inner attitude integration algorithm to improve attitude accuracy of the strapdown inertial attitude and heading reference system(SIAHRS),which,by means of a Kalman filter,integrates the calculated attitude from the accelerometers in inertial measuring unit(IMU),called damping attitudes,with those from the conventional IMU.As vehicle's acceleration could produce damping attitude errors,the horizontal outputs from accelerometers are firstly used to judge the vehicle's motion so as to determine whether the damping attitudes could be reasonably applied.This article also analyzes the limitation of this approach.Furthermore,it suggests a residual chi-square test to judge the validity of damping attitude measurement in real time,and accordingly puts forward proper information fusion strategy.Finally,the effectiveness of the proposed algorithm is proved through the experiments on a real system in dynamic and static states.展开更多
The transfer alignment problem of the shipborne weapon inertial navigation system （INS） is addressed. Specifically, two transfer alignment algorithms subjected to the ship motions induced by the waves are discussed....The transfer alignment problem of the shipborne weapon inertial navigation system （INS） is addressed. Specifically, two transfer alignment algorithms subjected to the ship motions induced by the waves are discussed. To consider the limited maneuver level performed by the ship, a new filter algorithm for transfer alignment methods using velocity and angular rate matching is first derived. And then an improved method using integrated velocity and integrated angular rate matching is introduced to reduce the effect of the ship body flexure. The simulation results show the feasibility and validity of the proposed transfer alignment algorithms.展开更多
文摘In the practice of control the industrial processes, proportional-integral-derivative controller remains pivotal due to its simple structure and system performance-oriented tuning process. In this paper are presented two approaches for synthesis the proportional-integral-derivative controller to the models of objects with inertia, that offer the procedure of system performance optimization based on maximum stability degree criterion. The proposed algorithms of system performance optimization were elaborated for model of objects with inertia second and third order and offer simple analytical expressions for tuning the PID controller. Validation and verification are conducted through computer simulations using MATLAB, demonstrating successful performance optimization and showcasing the effectiveness PID controllers’ tuning. The proposed approaches contribute insights to the field of control, offering a pathway for optimizing the performance of second and third-order inertial systems through robust controller synthesis.
文摘We have succeeded in 2-slit interference simulation by assuming that a travelling particle interacts with its environment, getting information on the environmental condition according to the adaptive dynamics by Ohya, thus proposed the possibility that the entanglement comes from the interaction with the environment (Ando et al., 2023). This concept means that there should be no isolated or inertial system other than our unique universe space. Taking this message into account and assuming that the signal velocity is constant against our unique universe space, we reconsidered the inertial system and relativity theory by Galilei and Einstein and found several misunderstandings and errors. Time delay and Lorentz shrinkage were derived similarly to the prediction by special relativity theory, but Lorentz transformation and 4-dimensional time/space view were not. They must have implicitly and unconsciously assumed that any signals transfer information without giving any influences to any systems different from our adaptive dynamical view. We propose that their relativity theories should be reinterpreted in view of adaptive dynamics.
文摘In this paper, I present evidence that there exists an unstructured area in the present general assumptions of classical mechanics, especially in case of rigid bodies exposed to simultaneous noncoaxial rotations. To address this, I propose dynamics hypotheses that lead to interesting results and numerous noteworthy scientific and technological applications. I constructed a new mathematical model in rotational field dynamics, and through this model, results based on a rational interpretation of the superposition of motions caused by torques were obtained. For this purpose, I analyze velocity and acceleration fields that are generated in an object with intrinsic angular momentum, and assessed new criteria for coupling velocities. In this context, I will discuss reactions and inertial fields that cannot be explained by classical mechanics. The experiments have been analyzed and explained in a video accompanying this text. I am not aware of any concurrent study on the subject and conclusions evidenced in this paper, preventing us from making additional theoretical com- parisons or indicate to the reader other sources to compare criteria.
基金the National Natural Science Foundation of China(Grant No.61403397)the Natural Science Basic Research Plan in Shaanxi Province of China(Grant Nos.2020JM-358,2015JM6313).
文摘Inertial system platforms are a kind of important precision devices,which have the characteristics of difficult acquisition for state data and small sample scale.Focusing on the model optimization for data-driven fault state prediction and quantitative degreemeasurement,a fast small-sample supersphere one-class SVMmodelingmethod using support vectors pre-selection is systematically studied in this paper.By theorem-proving the irrelevance between themodel’s learning result and the non-support vectors(NSVs),the distribution characters of the support vectors are analyzed.On this basis,a modeling method with selected samples having specific geometry character fromthe training sets is also proposed.The method can remarkably eliminate theNSVs and improve the algorithm’s efficiency.The experimental results testify that the scale of training samples and the modeling time consumption both give a sharply decrease using the support vectors pre-selection method.The experimental results on inertial devices also show good fault prediction capability and effectiveness of quantitative anomaly measurement.
文摘The physical nature of inertia is explored. Authors, based on Mach’s principle, offer hypothesis of the induction nature of inertia and theory, which allows extend the principle of relativity to the non-inertial reference systems. The system of differential equations, which eliminates the shortcomings of Newtonian mechanics and Special Theory of Relativity (STR) was composed according to this theory. Row of concrete calculations and explanations are made using the theory. Reason of constancy orbital velocities of galaxies is found out and way of its calculations is shown. Existence of dark matter and the new particles (neutralinos, axons, space vacuum etc.) is prejudiced. Axial deviation of the ray of light in gravitational field is explained and calculated. An example of calculation of the Mercury’s orbital motion is made and complex planets’ trajectories are explained by the action of new field with induction nature. Flat rotation of celestial bodies and shaping of planets’ rings (like the Saturn’s rings) are explained. Indistinguishability of Doppler and Einstein’s effects for terrestrial observer is shown.
文摘Microelectromechanical systems(MEMS)technology has gained significant attention over the past decade for measuring inertial angular velocity.However,due to inherent complexity,MEMS gyroscopes typically feature up to ten times more parameters than traditional sensors,making selection a challenging task even for experts.This study addresses this challenge,focusing on defensive guidance,navigation,and control(GNC)systems where precise and reliable angular velocity measurement is critical to overall performance.A comprehensive mathematical model is introduced to encapsulate all key MEMS parameters,accompanied by discussions on calibration and Allan variance interpretation.For six leading MEMS gyroscope applications,namely inertial navigation,integrated navigation,autopilot systems,rotating projectiles,homing guidance,and north finding,the most critical parameters are identified,distinguishing suitable and unsuitable sensor choices.Special emphasis is placed on inertial navigation systems,where practical rules of thumb for error evaluation are derived using six degrees of freedom motion equations.Rigorous simulations demonstrate the influence of various sensor parameters through real-world case studies,including static navigation,multi-rotor attitude estimation,gimbal stabilization,and north finding via a turntable.This work aims to be a beacon for practitioners across diverse fields,empowering them to make more informed design decisions.
基金Project(52078129)supported by the National Natural Science Foundation of ChinaProject(MTF2023009)supported by the Open Project of Key Laboratory of Transport Industry of Comprehensive Transportation Theory(Nanjing Modern Multimodal Transportation Laboratory),ChinaProject(2242024K40037)supported by the Fundamental Research Funds for the Central Universities,China。
文摘A shaking table test was performed to investigate the different responses of piles with and without cement-soil reinforcement,considering both inertial and kinematic interactions.A comparison of the dynamic shear stress−strain hysteresis curves of soil profiles on the pile side with and without cement-soil reinforced piles indicates that cement-soil reinforced piles not only bear more tremendous shear stress but also have smaller strains under the action of cyclic shear stress.Furthermore,the cement-soil on the pile side not only shares part of the shear stress and modifies the bending moment distribution but also significantly enhances the resistance of the pile-side soil,reducing the lateral displacement of the superstructure.Cement-soil reinforcement reduced shear strains,inhibited sand liquefaction,and reduced superstructure displacements by 27%−47%(instantaneous)and 40%−65%(permanent).The proportion of horizontal load sharing between cement-soil reinforcement and saturated sand is considered,along with the change pattern of the subgrade reaction after sand liquefaction.An equivalent subgrade reaction calculation method is proposed,which accounts for the horizontal load-sharing ratios of soils with two different strengths.The test results indicate that the pile stress and displacement,estimated using the equivalent subgrade reaction,are in good agreement with the observed results.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.12074399,12204500,and 12004403)the Key Projects of Intergovernmental International Scientific and Technological Innovation Cooperation(No.2021YFE0116700)+1 种基金the Shanghai Natural Science Foundation(No.20ZR1464400)the Shanghai Sailing Program(No.22YF1455300).
文摘The suppression of ablative Rayleigh–Taylor instability(ARTI)by a spatially modulated laser in inertial confinement fusion(ICF)is studied through numerical simulations.The results show that in the acceleration phase of ICF implosion,the growth of ARTI can be suppressed by using a short-wavelength spatially modulated laser.The ARTI growth rate decreases as the wavelength of the spatially modulated laser decreases,and ARTI is completely suppressed after a certain wavelength has been reached.A spatially uniform laser is introduced to keep the state of motion of the implosion fluid consistent,and it is found that the proportion of the spatially modulated laser required for complete suppression of ARTI decreases as the wavelength continues to decrease.We also optimize the spatial intensity distribution of the spatially modulated laser.In addition,as the duration of the spatially modulated laser decreases,the proportion required for completely suppressing ARTI increases,but the required energy decreases.When the perturbation wavenumber decreases,the wavelength of the spatially modulated laser required for complete suppression of ARTI becomes longer.In the case of multimode perturbation,ARTI can also be significantly suppressed by a spatially modulated laser,and the perturbation amplitude can be reduced to less than 10% of that without a spatially modulated laser.We believe that the conclusions drawn from our simulations can provide the basis for new approaches to control ARTI in ICF.
基金Supported by the National Natural Science Foundation of China(60702003)~~
文摘The principle of the inertial navigation system（INS） with rotating inertial measurement unit （IMU） is analyzed. A new IMU is established to rotate round each axis in three directions. Then, the related error models for the designed system during rotating are deduced and the improved system is built. Finally, the performance simulation of the proposed system is provided. The simulation result indicates that the designed system can improve the accuracy of the roll and the pitch as well as heading by rotating three axes, thus guaranting the heading accuracy. Moreover, based on the principle of rotation at six different positions, such structure can carry out real-time calibration, and improve the system performance.
文摘Based on error analysis, the influence of error sources on strapdown inertial navigation systems is discussed. And the maximum permissible component tolerances are established. In order to achieve the desired accuracy (defined by circular error probability), the types of appropriate sensors are chosen. The inertial measurement unit (IMU) is composed of those sensors. It is necessary to calibrate the sensors to obtain their error model coefficients of IMU. After calibration tests, the accuracy is calculated by uniform design method and it is proved that the accuracy of IMU is satisfied for the desired goal.
文摘A brand new method of automatic north seeking/sight stabilizing is introduced for usage in land fighting vehicles such as tank, etc. Some inertial devices are installed additionally on the platform along with relative control circuits to make its function of North seeking possible. Double position calculation is adopted in this method, and by alignment at two sites the azimuth angle can be figured out. Also the orientation and the horizontal shifts of the gyro are simultaneously measured and compensated so as to improve the accuracy of north seeking. The system can automatically seek north when the vehicle is immobile. And the time consumption is no more than 5.5 min. Besides, the system can keep azimuth angle and provide tilt angle and pitch angle of the vehicle.
文摘Due to the poor observability of INS ground self alignment, only horizontal alignment is satisfied. This paper proposes using GPS double difference carrier phase as external reference to improve the observability of INS self alignment. Through observability analysis and computer simulation, it is demonstrated that the azimuth alignment is as quick as horizontal alignment, the accuracy of horizontal alignment is improved, and the gyros errors can be estimated quickly and precisely.
文摘The cost of the gravity passive inertial navigation system will be lower witha rate azimuth platform and gravity sensor constituting a gravity measurement and navigationsystem. According to the system performance characteristics, we study the rate azimuth platforminertial navigation system (RAPINS), give the system navigation algorithm, error equations of theattitude, velocity and position of the rate azimuth platform, and random error models of theaccelerometer and gyro. Using the MATLAB/Simulink tools, we study the RAPINS and RAPINS withvelocity damping. Simulation results demonstrate that the RAPINS with velocity damping has smallerrors in platform attitude and position and satisfies gravity measurement and navigationrequirement.
基金supported by National Key Research and Development of China (No. 2017YFB1002800)
文摘With the development of micro-electromechanical systems(MEMS), miniaturized, low-power and low-cost inertial measurement units(IMUs) have been widely integrated into mobile terminals and smart wearable devices. This provides the prospect of a broad application for the inertial sensor-based pedestrian dead-reckoning(IPDR) systems. Especially for indoor navigation and indoor positioning, the IPDR systems have many unique advantages that other methods do not have. At present, a large number of technologies and methods for IPDR systems are proposed. In this paper, we have analyzed and outlined the IPDR systems based on about 80 documents in the field of IPDR in recent years. The article is structured in the form of an introduction-elucidation-conclusion framework. First, we proposed a general framework to explore the structure of an IPDR system. Then, according to this framework, the IPDR system was divided into six relatively independent sub-problems, which were discussed and summarized separately. Finally, we proposed a graph structure of IPDR systems, and a sub-directed graph, formed by selecting a combined path from the start node to the end node, skillfully constitutes a technical route of one specific IPDR system. At the end of the article, we summarized some key issues that need to be resolved before the IPDR systems are widely used.
文摘In this work,a fast and accurate stationary alignment method for strapdown inertial navigation system （SINS） is proposed. It has been demonstrated that the stationary alignment of SINS can be improved by employing the multiposition technique,but the alignment time of the azimuth error is relatively longer. Over here, the two-position alignment principle is presented. On the basis of this SINS error model, a fast estimation algorithm of the azimuth error for the initial alignment of SINS on stationary base is derived fully from the horizontal velocity outputs and the output rates, and the novel azimuth error estimation algorithm is used for the two-position alignment. Consequently, the speed and accuracy of the SINS＇ s initial alignment is enhanced greatly. The computer simulation results illustrate the efficiency of this alignment method.
基金financially supported by the National Natural Science Foundation of China (No. 50975055)
文摘A new simple and effective inertial parameter identification method based on sinusoidal vibrations of a six-degree-of-freedom parallel manipulator is proposed. Compared with previously known identification algorithms, the advantages of the new approach are there is no need to design the excitation trajectory to consider the condition number of the observation matrix and the inertial matrix can be accurately defined regardless of the effect of viscous friction. In addition, the use of a sinusoidal exciting trajectory allows calculation of the velocities and accelerations from the measured position response. Simulations show that the new approach has acceptable tolerance of dry friction when using a simple coupling parameter modified formula. The experimental application to the hydraulically driven Stewart platform demonstrates the capability and efficiency of the proposed identification method.
基金Project(60604011) supported by the National Natural Science Foundation of China
文摘To improve the accuracy of strapdown inertial navigation system(SINS) for long term applications,the rotation technique is employed to modulate the errors of the inertial sensors into periodically varied signals,and,as a result,to suppress the divergence of SINS errors.However,the errors of rotation platform will be introduced into SINS and might affect the final navigation accuracy.Considering the disadvantages of the conventional navigation computation scheme,an improved computation scheme of the SINS using rotation technique is proposed which can reduce the effects of the rotation platform errors.And,the error characteristics of the SINS with this navigation computation scheme are analyzed.Theoretical analysis,simulations and real test results show that the proposed navigation computation scheme outperforms the conventional navigation computation scheme,meanwhile reduces the requirement to the measurement accuracy of rotation angles.
基金the Nature Science Foundation of China under Grant No.60604019 and No.6075001
文摘The error equation of a rotating inertial navigation system was introduced. The effect of the system's main error source (constant drift of gyro and zero bias of accelerometer) under rotating conditions for the system was analyzed. Validity of theoretical analysis was shown via simulation, and that provides a theoretical foundation for a rotating strap-down inertial navigation system during actual experimentation and application.
基金Aeronautical Science Foundation of China(20080852011,20070852009)
文摘This article proposes a new inner attitude integration algorithm to improve attitude accuracy of the strapdown inertial attitude and heading reference system(SIAHRS),which,by means of a Kalman filter,integrates the calculated attitude from the accelerometers in inertial measuring unit(IMU),called damping attitudes,with those from the conventional IMU.As vehicle's acceleration could produce damping attitude errors,the horizontal outputs from accelerometers are firstly used to judge the vehicle's motion so as to determine whether the damping attitudes could be reasonably applied.This article also analyzes the limitation of this approach.Furthermore,it suggests a residual chi-square test to judge the validity of damping attitude measurement in real time,and accordingly puts forward proper information fusion strategy.Finally,the effectiveness of the proposed algorithm is proved through the experiments on a real system in dynamic and static states.
基金supported by the Weapon Equipment Research Foundation in Advance(514090909HT0141).
文摘The transfer alignment problem of the shipborne weapon inertial navigation system （INS） is addressed. Specifically, two transfer alignment algorithms subjected to the ship motions induced by the waves are discussed. To consider the limited maneuver level performed by the ship, a new filter algorithm for transfer alignment methods using velocity and angular rate matching is first derived. And then an improved method using integrated velocity and integrated angular rate matching is introduced to reduce the effect of the ship body flexure. The simulation results show the feasibility and validity of the proposed transfer alignment algorithms.
